The invention relates to analog circuits in an integrated circuit environment and, in particular embodiments, to low voltage integrated circuits having both digital and analog components.
As higher levels of circuit integration are achieved more analog functions are being mixed with digital functions on the same integrated circuit. In addition, as circuit dimensions shrink, integrated circuit supply voltages decrease. There is therefore a need in the art for techniques to facilitate the use of lower voltages in mixed integrated circuits.
The present invention discloses methods for providing a control signal for a programmable gain attenuator. First an initial value for a fine control portion of a programmable gain attenuator is set. An AGC portion of a control loop then compares an average absolute value of the signal controlled to a reference value. Once the value of the course AGC has converged sufficiently, the operation of the coarse AGC portion of the control loop is terminated and the operation of the fine control portion of the programmable attenuator is begun.